A Manhattan judge Friday ordered a psychiatric examination for a Princeton grad charged with fatally shooting his millionaire hedge-fund dad.

Thomas Gilbert Jr., 30, has been in custody since his arrest for allegedly blasting his father, Thomas Gilbert Sr., point-blank in the head Jan. 4.

“My client has a long history of psychiatric issues, and we believe at this time he is not competent,” said defense lawyer Alex Spiro after the brief hearing in Manhattan Supreme Court before Justice Melissa Jackson.

Spiro previously notified the court that he planned to put on a psychiatric defense.

Prosecutors claim that the trust-fund layabout murdered his father, the founder of hedge fund Wainscott Capital, after he’d slashed his $200 stipend.

His mother, Shelley, discovered her slain husband on the floor of their Beekman Place pad with a .40-caliber Glock resting on his chest.

Gilbert Jr. allegedly tried to stage the scene to look like a suicide, prosecutors said.